MDZ was a stopgap, maybe Hextall should have blown it up and not tried to be competitive, Voracek for example would have gotten a nice package of prospects and draft picks, better than Schenn. Losing would have landed multiple top five picks. That was probably a "bridge too far" for this organization.
And they've been competitive, they've made the playoffs two of the last three years, note that Toronto has also lost twice in the first round, but no one there is getting bent out of shape. That's because they can see their future is bright.
No matter what Hextall does, they're two years away from taking the next step, JT would not put them over the hump, because he would only strengthen a position of strength going forward, and not address other weaknesses. Myers and Sanheim need a couple years before they can handle playoff pressure for 20 minutes a night, we just saw Sanheim play an awful 1st period in the AHL playoffs. Konecny is still developing the two way game that will allow him to be mentioned in the same breath with Marchand (hopefully without the stupid dirty play). Provorov has improved but needs to handle the puck better in his own end (cut back on turnovers), Patrick is probably a couple years from elite or close to elite status. Llindblom is still adjusting to NHL speed. Ghost has to raise his game. Frost is 2-3 years from being an impact NHL player.
They're not five years away, but they're not there yet either.
In a couple years, the core will be playoff ready, and that's when you make the big move in the summer of 2020, with Hart in goal, with the defense set, with strength down the middle, the ED draft behind you, you make that move to finish out the job. Maybe you have to replace Lindblom or Voracek, lost in the ED, or another D-man, or a 30 goal scorer or . . .
Meanwhile, I expect steady improvement the next two years, some prospects will regress, some will step up, some will come out of nowhere - but there's safety in numbers, if we were depending on 3 or 4 we'd cross our fingers, but it's more like 9 or 10, so the odds are in our favor.